I believe Mugen made a point that using larger tubing robbed the engine of power. Below is a copy of tech notes off King's website. I read the same thing in a magazine too.

During the development, the performance test on the exhaust manifold by so many different specifications had been conducted and as a result, we were able to obtain many data. Some of them are as follows.

-1. 45mm diameter of the primary manifold is better than that of 48mm.
-2. When compared between 4-1 and 4-2-1, 4-2-1 is better in overall. General notion that 4-1 is for the high speed and 4-2-1 is good for the middle speed range is not necessary applicable to F20C.
-3. Exhaust manifold of standard specification was an ideal specification as expected. It is also a collector configuration aimed at the peak power output.
-4. Regrettably, however, since the emphasis is placed on the mass production, the standard parts have the different primary manifold lengths for each cylinder and therefore, the engine performance between 6000 and 9000rpm is not necessary the best.


2. Actual running test has confirmed the following:

-1. Since there is a brake master cylinder placed near the exhaust manifold, it is indispensable to place a heat insulation material such as heat insulation plate between the cylinder and the manifold. We have actually confirmed that there was overheating phenomenon when the test was run without such a heat insulation.


3. From the result of the test conducted, we decided the specification for Mugen

 

Its a bit risky...ever seen a Ti- header explode?

cheers

W

 

I read it a while back, but when Hyper Rev dyno'ed the Amuse header, it showed very good gains, close to the Mugen in mid-range, but stronger later on. When they had the R1 Titan coupled with the header, they made an average of 10-12hp from 6500 to 8500RPM. I consider that to be an excellent gain for just the header and exhaust on the F20C.

 

JL,

I agree, that is dramatic. Its really tough to tell what is really the power gains with this car. I throw my arms up in the air, giving up really. On the one hand everyone seems to have a dyno plot, but then you buy the stuff and dyno and find different results. If its not the air charge temp kicking the ECU into a richer mod. its a variation in the breathing or exhaust downstream.

It just seems to me there are way too many variables for anyone to make a firm conclusion. Perhaps the best thing is for one to buy an entire system from one company and stick to that company's program, otherwise its really a stab in the dark.

cheers

W

 

Wael,
I agree with you. Unfortunately for us Toda does not (that I am aware of) import exhausts for the AP1.

 

I think the R1 Titan had a lot to do with the gains. Don't you think?

 

I agree with you for the most part, Wael. But I trust in Amuse, because they don't make fancy parts just to be fancy, the parts are made so they can have the fastest NA AP1, and they do. For example, they do not make an intake, because they cannot improve upon the Mugen intake. They made a header, however, that is extremely similar to the Mugen, which means they probably found the best comprmise for track use, so it may not gain as much down low or in mid-range, but it probably more than makes up for that in the top-end. It is also about 5lbs lighter than the Mugen using the same material, which is quite substantial for the header alone, considering the Mugen is already almost half the weight of the stocker.

I totally understand what you mean, but to me Mugen isn't about the fastest car on the track, but it's fancy, it's reasonably high-performance that is great for street use as well.

I follow Amuse's developement on their parts for the AP1 closely, and the way they work and their results are really impressive.

 

Interesting that the Amuse header is 5lbs. lighter. Is it made of a different metal? If not, could it be that it is thinner and therefore louder? Not that noise is an issue for race cars, but most of us here have dual use vehicles that need to be tolerated on a daily basis.

 

[QUOTE]Originally posted by Wael El-Dasher
[B]
[snip]2. Actual running test has confirmed the following:

 

[QUOTE]Originally posted by Asura
[B]Interesting that the Amuse header is 5lbs. lighter.